(a) Technical Field
The present invention relates to a method for uniformly forming an alloy catalyst in a fuel electrode of a solid oxide electrolysis cell.
(b) Background Art
Recently, with rapid climate change and global warming, technologies capable of reducing the emission of the greenhouse gas, carbon dioxide, or utilizing the same are drawing attention. Although carbon dioxide capture and storage is the representative technology of reducing the emission of carbon dioxide, the capture and storage technology is limited in treatment capacity. Therefore, technologies of converting and utilizing carbon dioxide are drawing particular attention recently.
A representative example of carbon dioxide conversion is reverse water gas shift (RWGS). Through the reverse water gas shift reaction, carbon monoxide (CO) can be selectively produced from carbon dioxide (CO2) and hydrogen (H2). The produced carbon monoxide (CO) can be used as a fuel or as a raw material for the production of high value-added plastics.
The reverse water gas shift reaction can be achieved with high efficiency through high-temperature co-electrolysis of carbon dioxide and water (H2O), which leads to production of a synthesis gas (syngas) containing hydrogen. Because the process proceeds at high temperatures, it is outstandingly advantageous over other production technologies in terms of thermodynamics and kinetics. In addition, the production amount and selectivity of the product can be controlled by controlling the conversion rate of the reactant. Furthermore, the synthesis gas consisting primarily of carbon monoxide and hydrogen can be converted to high value-added chemicals, synthetic liquid fuels, etc. through follow-up processes.
Accordingly, high-temperature co-electrolysis technologies using solid oxide electrolysis cells are drawing a lot of interests recently. The solid oxide electrolysis cell is generally operated at high temperatures (700-1,000° C.). It is structurally safe because all structural components are in solid state and is suitable for high-temperature co-electrolysis because it is operable even when exposed to a hydrocarbon gas environment.
The existing solid oxide cell containing a nickel (Ni)-based fuel electrode as disclosed in Korean Patent Publication No. 10-2009-0061870 exhibits good catalytic activity and electrical conductivity for fuel oxidation, but improvement is necessary because it exhibits low conversion rate when reducing chemically stable carbon dioxide.
Although a method of using a nano-sized noble metal catalyst has been proposed to improve the carbon dioxide conversion catalytic activity of the solid oxide electrolysis cell, there are limitations due to high sintering temperature during the preparation of the solid oxide cell, high cost because of the use of a large amount of the noble metal catalyst, etc.